Fix missing __lock / __unlock.

This was noticed as srandom / random use those.

Fixes issue #2916.
fix ports upgrades due to version changes
bump sdl and sdl-image port versions
sanity test for port version causing retrieve
Merge pull request #2919 from waywardmonkeys/fix-random-libc-locking

Fix missing __lock / __unlock.
fix nm scanning; notice only U, C, T
handle some corner cases in EMULATE_FUNCTION_POINTER_CASTS, and add testing
website analytics
Fix typo.
Merge pull request #2922 from waywardmonkeys/fix-typo

Fix typo.
Test for va_arg support on struct types (disabled on nested struct)

va_arg is not yet supported on nested struct types (see
https://code.google.com/p/nativeclient/issues/detail?id=3815)
Implement TTF_FontLineSkip
add some slack to browser.test_sdl2_mouse
disable most websockify-using parts of sockets tests; #2700
fake cfgetospeed; #2926
Merge pull request #2921 from caiiiycuk/incoming

SDL_CreateRGBSurfaceFrom for surfaces with depth 32
Merge pull request #2924 from fhd/incoming

Implement TTF_FontLineSkip
Update simd.js for upstream changes.

The main change relevant to Emscripten here is that this includes the
fix for unaligned loads and stores.
[tracing] Add task tracing.
[tracing] Context data is used on the server side now.